Danny Duffy Keeps the Ball Down?

In his Minor League career, Danny Duffy had a 10.5 K/9, 2.8 BB/9, 0.5 HR/9, and generally blew the doors off the hinges when he was in the game. A short stint away from the game dinged him in some scouting reports, but when he returned, it was all systems go for the young lefty with mid-90s gas and multiple secondary pitches with bite and break.

Then Duffy spent 2011 putting up 105.1 innings of 7.43 K/9, 4.38 BB/9, 1.28 HR/9, and generally blew goats when he was in the game. Even a short offseason away from the game couldn’t undo that ding, and he came into the season mostly un-noticed in fantasy circles. He went into Tuesday night’s game against the Athletics owned in 3% of Yahoo leagues.

Should his six innings of eight-strikeout, four-walk, one-hit ball in a pitcher-friendly park against a pitcher-friendly lineup erase the memory of a half-season like Duffy had in 2011? Probably not. But unpacking why Duffy did well might help us decide if he is capable of doing so more often this season.

Even if last season had more than one problem, the home runs might have been the most disconcerting to the Royals. They pleaded with their starter to keep the ball down, but this heat map seems to tell the story of an inability to do so, at least against right-handers, who hit 1.3 home runs per nine inning off of Duffy last year.

But Duffy was listening. In the spring, he admitted that he was working on it to Dick Kaegel of MLB.com:

Duffy came into camp charged with throwing strikes and keeping the ball down. He certainly did that Friday.

“The main goal is getting that pitch efficiency up and I need to get the ball down and repeat my delivery a lot more. It’s the whole cliche thing, but it’s true. And I feel like I worked enough in the offseason to find a delivery that was comfortable for me,” he said.

Did he manage the feat Tuesday night? Duffy allowed five fly balls against three ground balls, but none of those left the park at least. Take a look at his pitch locations for the game. Though it seems as if he kept the ball down more successfully, it’s not completely clear if that was the case.

Over half of the dots are below the line, but that’s hardly conclusive. Perhaps the stadium, and its’ 80 park factor for right-handed home runs, helped stop a home run, perhaps not.

More likely, Duffy was successful because he managed to elicit 14 swinging strikes in 103 pitches. Last year, he had a below-average 7.7% swinging strike rate, despite owning swing-and-miss stuff according to most scouts. According to Brooks Baseball, 71 of his 103 pitches were fastballs Tuesday, so he didn’t succeed by focusing on his off-speed stuff.

Then again, by linear weights, the fastball was his best pitch yesterday. Brooks had the pitch showing 10.8 inches of horizontal run, and our PITCH f/x leaderboards had Duffy in the top 20 in that sort of movement on the fastball. So maybe the fastball is his best pitch. In starting rotations around the league, only David Price, Derek Holland and CC Sabathia use their left hand to throw faster fastballs than Danny Duffy. Maybe his optimal usage of the pitch is closer to 70% than last year’s 60%.

Then again, Duffy’s changeup and curveball combined for nine swinging strikes on 30 pitches yesterday, so he’s not without secondary pitches. If all he has to do is keep the ball down, consider yesterday a possible step forward, but the key to his future may be simple: strike more batters out, and walk fewer. His Minor League career suggests that he can do both, but his rookie year suggests that you be cautious in picking him up — consider him a lock in anything deeper than 12-team mixed. Those that are desperate for upside on their staff could pick him up in shallower leagues, but perhaps sit him for his next start just to be safe.